WHAT more can Iran’s ruthless rulers do to squash their opponents? Since nationwide protests broke out last June over the disputed results of presidential elections, the official winner, Mahmoud Ahmadinejad, has pulled few punches. His security apparatus has beaten and arrested thousands, tried scores of dissidents in kangaroo courts, hounded others into exile, throttled the press and jammed the airwaves. But the massive and violent demonstrations that engulfed the capital, Tehran, and other cities on December 26th and 27th suggested that repression only deepens and broadens the opposition.